Tape Measure with Extended Standout

ABSTRACT

A tape measure comprises a main case having first and second sidewalls and a peripheral wall extending between the sidewalls; a flexible tape blade selectively deployable from the case; the tape blade having a generally curved cross-sectional profile when deployed from the main case and having a generally flat profile when retracted into the main case; a hook attached to a first end of the tape blade so as to be movable a distance along a longitudinal axis of the tape blade; the hook having a first section disposed generally parallel to the longitudinal axis and a second section connected thereto and disposed generally normal to the longitudinal axis, the hook comprising titanium and having a weight factor of not more than about 0.60. The tape blade may advantageously be not more than about 1.10 inch in width and have a standout of at least 9½ feet.

This is a continuation of U.S. patent application Ser. No. 11/519,743,filed 12 Sep. 2006, which is a continuation of U.S. patent applicationSer. No. 11/013,858, filed 16 Dec. 2004, which claims the benefit ofU.S. Provisional Application No. 60/533,093, filed 30 Dec. 2003. Thedisclosures of all the aforementioned applications are incorporatedherein by reference.

BACKGROUND OF THE INVENTION

The present invention is directed generally to tape measures, and moreparticularly to power return tape measures.

Modern tape measures (or “tape rules”) typically include a coiled tapethat is spring-biased towards a retracted position. A housing generallysurrounds and protects the tape and a retraction spring and includes anopening through which a distal end of the tape extends. Typically, thetape measure housing consists of two housing halves that are joinedtogether by one or more screws. In addition, one of the housing halvestypically includes an inwardly pointing integral post that provides ananchoring point for one end of the retraction spring. During assembly,the reel is placed over the post with the retraction spring engaged bythe post, and the other housing half is then joined to the first housinghalf with blade winding reel captured therebetween. During use, thedistal end of the tape blade is pulled away from the housing; whenreleased, the spring pulls the tape blade back into the housing so thatthe tape returns to the retracted position. The retracted tape blade istypically wound on the reel that is in turn rotatably supported by thehousing.

One aspect of tape measures that is considered by consumers is “bladestandout,” which is the distance that the measuring blade may beextended out from the housing before it buckles (folds over). Thegeneral perception in the marketplace is that longer standout is moredesirable, as it allows for the tape blade to span longer distances,such as between rafters of a house under construction.

While a number of approaches have been taken to increase standout, nonehave proven entirely satisfactory. As such, there remains a need forimproved tape measure designs, particularly those that provide a greaterstandout than standard designs.

SUMMARY OF THE INVENTION

The present invention is directed to a tape measure. In one embodiment,the tape measure comprises a main case having first and second sidewallsand a peripheral wall extending between the sidewalls; a flexible tapeblade selectively deployable from the case; the tape blade having agenerally curved cross-sectional profile when deployed from the maincase and having a generally flat profile when retracted into the maincase; a hook attached to a first end of the tape blade so as to bemovable a distance along a longitudinal axis of the tape blade; the hookhaving a first section disposed generally parallel to the longitudinalaxis and a second section connected thereto and disposed generallynormal to the longitudinal axis; the hook comprising titanium and havinga weight factor of not more than about 0.60. The hook may consistessentially of titanium. The tape blade may advantageously be not morethan about 1.10 inch in width and have a standout of at least 9½ feet,such as a standout of between 9½ feet and about 10½ feet. The blade mayadvantageously be subject to a retraction bias. The blade may comprise adistal end portion, an inner end portion, and an expected bucklingregion therebetween; the distal end portion being deployed before theexpected buckling region and the inner end portion when the blade isdeployed from the main case; and the assembly may further comprise areinforcement attached to the blade in the expected buckling region, thedistal end portion and the inner end portion being free of thereinforcement, with the expected buckling region including a locationwhere the blade would normally buckle in a standout test absent thereinforcement.

In another embodiment, the tape measure comprises a main case havingfirst and second sidewalls and a peripheral wall extending between thesidewalls; a flexible tape blade selectively deployable from the case;the tape blade having a generally curved cross-sectional profile whendeployed from the main case and having a generally flat profile whenretracted into the main case; the blade comprising a distal end portion,an inner end portion, and an expected buckling region therebetween; thedistal end portion being deployed before the expected buckling regionand the inner end portion when the blade is deployed from the case; ahook attached to the distal end portion of the tape blade so as to bemovable a distance along a longitudinal axis of the tape blade; the hookcomprising a first section disposed generally parallel to thelongitudinal axis and a second section connected thereto and disposedgenerally normal to the longitudinal axis; a reinforcement distinct frombut attached to the blade in the expected buckling region, the distalend portion and the inner end portion being free of the reinforcement;the expected buckling region including a location where the blade wouldnormally buckle in a standout test absent the reinforcement. Thereinforcement may comprise a metallic plate. The reinforcement maycomprise a longitudinally disposed fiber reinforcement, advantageouslywith the fiber reinforcement comprising a material selected from thegroup consisting of carbon and aramid. The reinforcement mayadvantageously be attached to the blade in the expected buckling regionby adhesive and/or the reinforcement may be attached to the blade on anupper side thereof. The expected buckling region may be located betweenabout nine and ten-and-one-half feet from the hook. The hook mayadvantageously have a weight factor not more than about 0.60.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a side view of one tape measure embodiment constructed inaccordance with the present invention.

FIG. 2 is a perspective view of one embodiment of a tape measure housingin accordance with the present invention with some elements removed forclarity (e.g., screws, clip, etc.).

FIG. 3 is a cross-section of one embodiment of an end hook according tothe present invention along the longitudinal axis of the blade.

FIG. 4 is side view of a the tape measure of FIG. 1 with the bladeextended.

FIGS. 5A-F show cross-sectional views of various embodiments of the tapeblade suitable for use in the present invention.

FIG. 6 shows a blade standout test fixture.

DETAILED DESCRIPTION OF THE INVENTION

As illustrated in FIG. 1, a tape measure, generally designated 10, isshown constructed according to the present invention. The tape measure10 includes a coilable measuring tape blade 40 and an associated housing20. An end hook 70 is attached to the distal end of the tape 40. Atape-biasing device, such as a retraction spring (not shown), isoperatively connected to the tape 40 to bias it towards a retractedorientation. A locking mechanism, including a toggle 16 or similaractuator is provided to aid in controlling the movement of the tape 40into and out of the housing 20. One or both sides of the housing 20 mayinclude a clip 18, as desired.

The housing 20 typically includes a main case or shell 30 and a gripelement 36 mounted on the shell 30. The housing 20 preferably has agenerally squarish shape, with a rounded upper-rear corner and may havea slightly projecting nose, as shown in FIGS. 1-2. The housing 20includes an opposing pair of sidewalls 32 and an interconnectingperipheral wall 34 that help define an internal chamber that houses thecoiled portion of the tape 40, a suitable tape-biasing device, andportions of the locking mechanism. As shown in the Figures, theperipheral wall 34, and thus the shell 30, may be thought of as having atop 22, a bottom 24, a front 26, and a rear 28. The housing 20 includesan opening 27 typically located near its lower front corner thatconnects to the internal chamber. The distal end of the tape 40 extendsthrough this opening 27. The housing 20 is preferably sized to fitwithin a user's hand, and also conveniently stored on a work belt or ina toolbox.

As shown in FIG. 2, the shell 30 may be constructed from two portions, aright-hand portion 30 a and a left-hand portion 30 b, joined together bysuitable screws 38, as is known in the art. The external configurationsof both the shell portions 30 a,30 b and the grip element portions 36may advantageously be symmetrical if desired, but this is not required.Indeed, the two portions 30 a,30 b may have different internal andexternal configurations, depending on the internal workings of the tapemeasure 10, as is known in the art. However, as the present inventionprimarily relates to the tape blade 40 and the hook 70, the details ofthe external configuration of the shell 30 are not important tounderstanding the present invention. More information on possibleexternal configurations of the housing 20 may be found in U.S. PatentApplication Publication 2003/0233762, which is incorporated herein byreference. Attention is also directed to U.S. Pat. Nos. 4,527,334;4,976,048; and 6,349,482; and 6,718,649; which are all incorporatedherein by reference, for further discussion of the general design andoperation of power return tape measures 10.

The tape blade 40 is designed to be selectively deployable from thehousing 20, and locked against the retraction force by locking means 16.The tape blade 40 is typically made from steel and assumes a generallycurved cross-sectional profile when deployed from the housing 20 and agenerally flat cross-sectional profile when retracted into the housing20. The blade typically has printing or other length indicia on an upperside 42, but is typically blank on a lower side 44. The tape blade 40 isalso typically coated with a protective coating, such as that describedin U.S. Patent Application Publication 2004/0071869,” which isincorporated herein by reference. The tape blade 40 may be thought of ashaving a distal end portion 52, an expected buckling region 54, and aninner end portion 56 disposed along a longitudinal axis 46. When theblade 40 is deployed from the housing 20, the distal end portion 52(with the hook 70 attached thereto) is deployed first, followed by theexpected buckling region 54, and then the inner end portion 56. Theblade 40 typically has a uniform cross-sectional thickness T_(U) in atleast the distal end portion 52 and the inner end portion 56, possiblythroughout, but may have a non-uniform cross-sectional thickness in theexpected buckling region 54. The expected buckling region 54 includes alocation B that corresponds to the expected buckling point when theblade is subjected to a standout test, based on an assumption that theblade has a uniform cross-sectional thickness throughout. The locationof point B may be derived theoretically or empirically. This expectedbuckling point B is spaced from the distal tip of the blade 40 by adistance L which is advantageously between eight and ten-and-one-halffeet.

The tape blade 40 may have a uniform thickness T_(U), both incross-section and along its entire length, and a uniform materialcomposition across its cross-section. See FIG. 5A. Alternatively, thetape blade 40 may have a thickness that varies across its cross-section(at least in the expected buckling region) and/or along its lengthand/or a varying material composition, or any combination thereof. Forexample, the thickness of the tape blade 40 may be thinner in the distalend portion of the blade 52, with a greater but uniform thickness T_(R)in the longitudinal region where buckling is expected to occur. In otherembodiments, the blade 40 may have integral longitudinal stiffeningmeans 60 distributed across its cross-section. For example, thewidthwise outer portions of the blade's cross-section may have athickness of T_(R), which is larger than the thickness T_(U) of middleportion of the blade's lateral cross-section (see FIG. 5B, 5E, 5F).Alternatively, the widthwise outer portions of the blade's cross-sectionmay have built-in longitudinal reinforcing members 60, such aslongitudinally oriented carbon or aramid fibers 64 or the like (see FIG.5C). Further still, the longitudinal reinforcing members 60 may take theform of carbon or aramid fiber mesh material embedded in the mainmaterial of the blade. It should be noted that the variations in theblade geometry and composition discussed above are intended to increasethe buckling resistance of the blade so as to increase the blade'sstandout. Such reinforcement means should be present in at least theexpected buckling region 54 of the blade 40, but may optionally extendfrom the expected buckling region 54 through the inner end portion 56 ofthe blade 40 (e.g., where the blade connects to the retraction spring).In still other embodiments, the blade 40 is provided with a thickercoating in the expected buckling region 54, and/or is provided with anreinforcing plate 62 attached to the blade 40 (e.g., riveted, bonded, orotherwise adhered) in the expected buckling region 54 (see FIG. 5D).While the reinforcing plate 62 is shown proximate upper side 42 in FIG.5D, the reinforcing plate may alternatively be proximate the lower side44, or there may be a reinforcing plate 62 on each side 42,44 of theblade 40 if desired. And, the various approaches discussed above may beused alone or in any combination in order to increase the standout ofthe blade 40.

The end hook 70 is attached to the distal end portion 52 of the blade40. The end hook 70 typically serves the dual function of providing ameans to hook or attach the tape blade 40 to a distant point and alsopreventing the blade 40 from being over-retracted into the housing. Thehook 70 includes a first section 72 that is disposed generally parallelto the longitudinal axis 46 of the blade 40 and a second section 76 thatis disposed generally perpendicular to the longitudinal axis 46 of theblade 40, with a suitable bend 78 therebetween. In the field, the firstsection 72 is sometimes referred to as the hook tongue, while the secondsection 76 is sometimes referred to as hook tip. The hook first section72 may advantageously have a curved shape that corresponds to theconcave curve of the blade's cross-section when deployed. The firstsection 72 may also advantageously include one or more (e.g., four)holes 74 employed to attach the hook 70 to the upper side 42 of blade 40via suitable attachment means such as rivets or the like. These holes 74may have a slightly larger size than the corresponding attachment meansso as to allow the hook 70 to move relative to the blade 40 by an amountX that is advantageously the thickness of the hook second section 76 soas to allow for inside or outside measurements. Further, the holes 74may be positioned to allow for proper retraction stop load distribution,see U.S. Pat. No. 5,659,970, which is incorporated herein by reference.The second section 76 of the hook may include a suitable center hole(not shown), typically an oval shaped hole, for accepting the exposedhead of a nail to allow the tape measure 10 to be rotated about thenail. Further, the second section 76 may, if desired, include one ormore magnets (not shown) to allow the hook 70 to be magneticallyattached to a surface or measurement point.

In the prior art, hooks for tape measures have been made from steel dueto the required strength and durability. For example, high quality tapemeasures are required to have hooks that can withstand repeatedretractions of the blade, such as ≧2,000 retractions. While low carbonsteel (i.e., type 1050) is suitable for such an application, steel is arelatively heavy material. The inventors of the present invention havediscovered that the additional weight of steel end hooks at the end ofthe tape blade negatively impacts the standout of the blade 40. Inparticular, it has been discovered that the standout can be increased ifthe weight of the hook 70 is reduced. However, simply making the hook 70dimensionally smaller negatively affects the strength, durability, andutility of the hook 70, particularly after repeated retractions of theblade 40. As such, preferred embodiments of the present inventionutilize a hook 70 having a weight factor of not more than about 0.60,where the term “weight factor,” as used herein, means the weight ratioof the hook 70 versus a dimensionally identical steel hook. For example,some embodiments of the present invention with approximately one inchwide blades 40 have a hook 70 that is made from titanium or a titaniumalloy in order to maintain the required durability, with the titaniumhook 70 having a weight of 2.27 grams-force versus a dimensionallyidentical steel hook with a weight of 4.08 grams-force, for a resultingweight factor of 0.556. Thus, the weight of the hook 70 at the end ofthe blade 40 is cut almost in half, while maintaining the desireddimensions and durability.

The tape measure 10 of the present invention has, due to itsconstruction, improved standout. One approach to measuring standout isto extend the blade 40 from the housing 20 until the blade 40 collapsesunder its own weight (commonly referred to in the art as “buckling” or“breaking over”). The use of a standard fixture allows for comparisonbetween different tape measure configurations. An example of one fixture90 that may be used is shown in FIG. 6. The fixture 90 includes asupport pylon 92 of height four inches with a ½ inch radiused upperedge. The support pylon 92 may include two roll pins 94 (e.g., ⅛ inchroll pins) or other means to prevent sideways slippage of the blade 40.A horizontal pin 96 of one inch diameter is placed six inches back fromthe center of the pylon 92 so as to leave a 7/32 of an inch gap betweenthe horizontal pin 96 and a floor flange 98. The tape measure 10 isplaced behind the horizontal pin 96, and the blade 40 is routed over thesupport pylon 92. The blade 40 is slowly extended until breakoveroccurs. The distance from the centerline of the support pylon 92 to hook70 (more precisely, the distal face of the second section 76), with thehook 70 present, is the amount of standout. In most embodiments, thetape measure 10 according to the present invention has a standout of atleast 9½ feet with an approximately one inch wide blade 40.

Tests were run to show that the use of a hook 70 with a weight factor of0.60 or less resulted in improved standout. Two types of existingproducts with steel end hooks were measured using a version of the testprocedure outlined above. In the test, the rivets holding the steel endhook 70 to the tape blade 40 were removed to release the steel hook. Thesteel hook and the rivets were then attached to the end of the blade 40using clear plastic tape, and the standout was measured three times foreach sample in this configuration using the fixture 90 described above.The steel hook was removed, and a titanium hook 70 of the same formfactor was then attached to the end of the same blade 40 (along with therivets) using the clear plastic tape. The standout was then measuredthree times for each sample using the fixture 90 described above. Theweight of the steel hook was 0.0084 pounds, and the weight of thetitanium hook 70 was 0.0046 pounds. Thus, the test compared the standoutresults using hooks of different weight factors, with all othervariables being equal. The results are presented in the followingTable 1. TABLE 1 Standout Results (inches) Lufkin ® 2125 Tape Lufkin ®PS3425 Tape Titanium Titanium Sample Steel Hook Hook Sample Steel HookHook 1A 82.0 84.0 6A 82.5 87.5 1B 81.5 84.0 6B 82.0 86.5 1C 81.5 84.5 6C82.5 87.0 2A 76.0 82.0 7A 85.0 87.5 2B 76.0 82.0 7B 84.5 87.5 2C 76.082.0 7C 87.0 87.0 3A 75.5 80.5 8A 85.0 85.0 3B 75.0 81.0 8B 85.0 87.0 3C75.5 81.0 8C 85.0 86.5 4A 82.0 83.5 9A 84.5 87.0 4B 82.0 85.0 9B 84.586.0 4C 82.0 83.0 9C 84.5 86.5 5A 83.0 84.0 10A  82.5 85.5 5B 82.0 85.010B  82.5 87.0 5C 83.0 85.0 10C  82.5 87.0 Average 79.5 83.1 Average83.8 86.7These test results show that use of the hook with a weight factor ofless than 0.60 results in an increased standout. For the Lufkin® 2125tape blade, the standout increase was approximately 3.6 inches onaverage. For the Lufkin® PS3425 tape blade, the standout increase wasapproximately 2.9 inches on average.

Another series of tests were run using a Max Steel® tape measure,available from The Stanley Works of New Britain, Conn. This tape measureused a blade with a width of one inch and an available measurementlength of twenty-five feet. The tests were similar in procedure to thosegiven above, with the weight of the steel hook was 0.0086 pounds, andthe weight of the titanium hook 70 was 0.0051 pounds. Thus, the testcompared the standout results using hooks of different weight factors,with all other variables being equal. The results are presented in theTable 2. TABLE 2 Standout Results (inches) Max Steel ® Tape Sample SteelHook Titanium Hook 1A 90.0 102.0 1B 90.5 104.0 1C 90.5 104.5 2A 99.0103.0 2B 99.0 103.0 2C 99.0 104.0 Average 94.7 103.4These test results show that use of the hook with a weight factor ofless than 0.60 results in an increased standout. For the Max Steel® tapeblade, the standout increase was approximately 8.7 inches on average.

While the test results given above are for tape measures with standoutlengths less than 9½ feet, one of ordinary skill in the art should beable to further increase the standout provided by the use of the endhook with a weight factor of less than 0.60 using the teachings of U.S.Pat. No. 6,324,769 (incorporated herein by reference) to increase thestandout to the desired length. Alternatively, one of ordinary skill inthe art should be able to further increase the standout provided by theuse of the end hook with a weight factor of less than 0.60 using theother teachings of the present disclosure (e.g., blade reinforcementmeans 60).

It should be understood that the tape measures 10 of the presentinvention may also include other features, such as shock-absorbingbumpers proximate the opening 27, specially coated blades, variouslocking mechanisms, hook reinforcing plates, and like, all of which areknown in the art.

The present invention may, of course, be carried out in other specificways than those herein set forth without departing from the essentialcharacteristics of the invention. The present embodiments are,therefore, to be considered in all respects as illustrative and notrestrictive, and all changes coming within the meaning and equivalencyrange of the appended claims are intended to be embraced therein.

1. A tape measure, comprising: a main case having first and secondsidewalls and a peripheral wall extending between said sidewalls; aflexible tape blade selectively deployable from said case; said tapeblade having a generally curved cross-sectional profile when deployedfrom said main case and having a generally flat profile when retractedinto said main case; a hook attached to a first end of said tape bladeso as to be movable a distance along a longitudinal axis of said tapeblade; said hook having a first section disposed generally parallel tosaid longitudinal axis and a second section connected thereto anddisposed generally normal to said longitudinal axis, said hookcomprising titanium and having a weight factor of not more than about0.60.
 2. The tape measure of claim 1 wherein said hook consistsessentially of titanium.
 3. The tape measure of claim 1 wherein saidtape blade is not more than about 1.10 inch in width and has a standoutof at least 9½ feet.
 4. The tape measure of claim 3 wherein said tapeblade has a standout of between 9½ feet and about 10 feet.
 5. The tapemeasure of claim 1: wherein said blade is subject to a retraction bias;wherein said tape blade is not more than about 1.10 inch in width andhas a standout of at least 9½ feet.
 6. The tape measure of claim 1:wherein said blade comprises a distal end portion, an inner end portion,and an expected buckling region therebetween; said distal end portionbeing deployed before said expected buckling region and said inner endportion when said blade is deployed from said main case; furthercomprising a reinforcement attached to said blade in said expectedbuckling region, said distal end portion and said inner end portionbeing free of said reinforcement; and wherein said expected bucklingregion includes a location where said blade would normally buckle in astandout test absent said reinforcement.
 7. The tape measure of claim 6wherein said tape blade is not more than about 1.10 inch in width andhas a standout of at least 9½ feet.
 8. A tape measure, comprising: amain case having first and second sidewalls and a peripheral wallextending between said sidewalls; a flexible tape blade selectivelydeployable from said case; said tape blade having a generally curvedcross-sectional profile when deployed from said main case and having agenerally flat profile when retracted into said main case; said bladecomprising a distal end portion, an inner end portion, and an expectedbuckling region therebetween; said distal end portion being deployedbefore said expected buckling region and said inner end portion whensaid blade is deployed from said case; a hook attached to said distalend portion of said tape blade so as to be movable a distance along alongitudinal axis of said tape blade; said hook comprising a firstsection disposed generally parallel to said longitudinal axis and asecond section connected thereto and disposed generally normal to saidlongitudinal axis; a reinforcement distinct from but permanentlyattached to said blade in said expected buckling region, said distal endportion and said inner end portion being free of said reinforcement;said expected buckling region including a location where said bladewould normally buckle in a standout test absent said reinforcement. 9.The tape measure of claim 8 wherein said reinforcement comprises ametallic plate.
 10. The tape measure of claim 8 wherein saidreinforcement comprises a longitudinally disposed fiber reinforcement.11. The tape measure of claim 13 wherein said fiber reinforcementcomprises a material selected from the group consisting of carbon andaramid.
 12. The tape measure of claim 8 wherein said reinforcement isattached to said blade in said expected buckling region by adhesive. 13.The tape measure of claim 8 wherein said expected buckling region islocated between about nine and ten-and-one-half feet from said hook. 14.The tape measure of claim 8 wherein said hook has a weight factor notmore than about 0.60.
 15. The tape measure of claim 8 wherein saidreinforcement is attached to said blade on an upper side thereof. 16.The tape measure of claim 8: wherein said expected buckling region islocated between about nine and ten-and-one-half feet from said hook;wherein said hook has a weight factor not more than about 0.60; andwherein said reinforcement comprises a metallic plate.
 17. The tapemeasure of claim 8: wherein said expected buckling region is locatedbetween about nine and ten feet from said hook; wherein saidreinforcement comprises a longitudinally disposed fiber reinforcement,said fiber reinforcement comprising a material selected from the groupconsisting of carbon and aramid; and wherein said hook has a weightfactor not more than about 0.60.